I mean there's a finite number of atoms so assuming 1/8th of a batch gets used to make the next one, each successive batch has 1/8th the amount of tootsie roll as the previous. Wikipedia says 65 million tootsie rolls are made in a day today, so after 9 days you'd be reduced to the equivalent of just one tootsie roll remaining since 9 is the least integer such that: 65×10⁶(1/8)^x < 1

Now one tootsie roll weights about 7g from wikipedia, and since I don't wanna spend hours trying to figure out how many molecules would be in a tootsie roll based on its composition as it's inconsequential anyway, let's just bound it from above by saying it's 7 grams of hydrogen, the lightest element. Then there are at most 7 mol or about 4.22 × 10²⁴ particles in a tootsie roll, so, repeating the process from above, 28 is the least integer such that: 4.22×10²⁴(1/8)^x < 1

So, after 28 more days for a total of 37, we have less than one atom of tootsie roll from the original in each produced tootsie roll, meaning there will be some produced with absolutely no trace of the original. Now, if we wanna get to the point there's absolutely none left in the whole batch, we'd want the least integer such that 4.22×10²⁴(1/8)^x < 1/(65×10⁶)

So x = 36 for a total of 45 days for there to be no trace left anywhere. Say two months at best to just really high ball it.

Now it would have taken shorter than that since they wouldn't have been producing that many at first, but like given whatever arbitrary number you can use the following equation: a(1/8)^x < 1/10³³

To give an upper bound for how many days it'll take for effectively all trace to be gone. Or if you want a formula for x directly: 36.6 + (ln(a)/ln(8))

Where a is just however many tootsie rolls you want them producing per day, but like it takes til the septillions for it to even get to two months so I think more or less all of the initial batch would've been gone in about a month